The present invention relates to sprinklers used to irrigate lawns, playing fields, golf courses and the like, and more particularly, to an irrigation sprinkler that can be serviced from the top of the sprinkler without having to excavate the same.
Sprinklers have long been used to water turf and other vegetation. Many designs have been developed with the goal of uniformly distributing a desired precipitation rate over a given area. One of the most common type of sprinklers is the pop-up type that is normally mounted in a sub-surface location so that the top of the sprinkler is substantially at ground level. When water pressure is applied, a riser with a nozzle at its upper end extends and delivers a spray of water over the adjacent area. When the water pressure is terminated, a spring retracts the riser so that the upper end of the nozzle is flush with the head of the sprinkler. This removes the sprinkler as an obstacle to play occurring on the turf and allows the turf to be mowed.
So-called rotor type pop-up sprinklers having internal water turbines for rotating their nozzles have been developed and widely commercialized. Furthermore, pop-up sprinklers with diaphragm type valves incorporated into the same are widely utilized. A common type of pop-up sprinkler has an internal diaphragm valve which is opened and closed by a solenoid or a hydraulically operated pilot valve. The diaphragm valve controls the entry of water into the outer case or housing of the sprinkler from a pressurized supply pipe or line to which it is connected. In many cases during the life of a so-called “valve-in-head” sprinkler the diaphragm valve will fail, often due to debris damaging the diaphragm valve seat or clogging the small passages in the diaphragm valve. The thin flexible diaphragm may also wear out. It is then necessary to shut off the water supply and dig up the sprinkler so that the defective diaphragm valve components can be repaired, or the sprinkler replaced in its entirety. This is a relatively expensive, tedious and time consuming process. Excavation of the defective sprinkler can also cause considerable damage to the surrounding landscaping.
U.S. Pat. No. 5,871,156 of Lawson assigned to Anthony Manufacturing Corporation discloses an impact type pop-up sprinkler having a valve seat that is removable from the top of the sprinkler case, without disconnecting the case from the water supply. However, impact type sprinklers are noisy, inaccurate in terms of arc coverage, and prone to breakage. In addition, it is necessary to individually disassemble and reassemble the various components of the diaphragm valve in order to gain access to the valve seat which must be unscrewed from the outer case. This part-by-part disassembly and re-assembly can be a difficult task for landscape maintenance personnel who are often simply gardeners.
It would therefore be desirable to provide a pop-up sprinkler with a turbine driven rotor and a diaphragm valve assembly that could be more readily serviced from the top of the sprinkler without having to dig up or otherwise disconnect the sprinkler from its supply line.